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Flexural behaviour of a new timber-concrete composite structural flooring system. Full scale testing

https://research.thinkwood.com/en/permalink/catalogue3314
Year of Publication
2023
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Martín-Gutiérrez, Emilio
Estévez-Cimadevila, Javier
Suárez-Riestra, Félix
Otero-Chans, Dolores
Organization
University of Coruña
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Timber Flooring System
Flexural Behaviour
Four-point Bending Test
Research Status
Complete
Series
Journal of Building Engineering
Summary
Timber-concrete composite systems are a high-performance alternative for building floors, of great interest in the current context of environmental concerns. Looking for a more eco-friendly solution, the paper presents a new flooring system with a wood-concrete connection that does not require adhesives or special metal elements. Four-point bending tests were performed on TCC flooring samples with a span of 6.0, 7.2 and 8.4 m. Its cross section was a prefabricated piece in the shape of an inverted T made up of a lower glulam flange, glued together with a central plywood rib with aligned holes in its upper part that go through the entire thickness of the plywood. The set was completed with a top layer of poured-in-place concrete. The connection between both materials is achieved by penetrating the concrete into the rib holes. Additionally, corrugated steel bars were placed through said holes to achieve ductile behaviour. In all cases, a slenderness ratio of L/24 was used. The experimental results showed that the lowest value of ultimate load obtained was 4.3 times higher than the total service load estimated for a building for public use (9 kN/m2). The maximum deflection of the total load was between L/573 and L/709 for the loads corresponding to a building for public use (9 kN/m2) and between L/1069 and L/1340 for the case of residential type building (5 kN/m2). An analysis of the effects of vibrations in the service limit state in relation to user comfort has been included. The results indicate that the system satisfies the requirements for the intended uses. Consequently, the proposed solution shows its effectiveness both in terms of strength and stiffness for the construction of light floors, being easy to build and having high performance.
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Analysis Behavior of Openings on Full-Size Cross-Laminated Timber (CLT) Frame Shear Walls Tested Monotonically

https://research.thinkwood.com/en/permalink/catalogue3335
Year of Publication
2023
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Dungani, Rudi
Sulistyono
Karliati, Tati
Suhaya, Yoyo
Malik, Jamaludin
Alpian
Supriyati, Wahyu
Organization
Institut Teknologi Bandung
Kuningan University
Palangka Raya University
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Monotonic Test
Seismic Resistance
Wood-Frame
Opening
Research Status
Complete
Series
Forests
Summary
Walls, as components of the lateral-force-resisting system of a building, are defined as shear walls. This study aims to determine the behavior of shear wall panel cross-laminated-timber-based mangium wood (Acacia mangium Willd) (CLT-mangium) in earthquake-resistant prefabricated houses. The earthquake performance of CLT mangium frame shear walls panels has been studied using monotonic tests. The shear walls were constructed using CLT-mangium measuring 2400 mm × 1200 mm × 68 mm with various design patterns (straight sheathing, diagonal sheathing/45°, windowed shear wall with diagonal pattern and a door shear wall with a diagonal pattern). Shear wall testing was carried out using a racking test, and seismic force calculations were obtained using static equivalent earthquake analysis. CLT-mangium sheathing installed horizontally (straight sheathing) is relatively weak compared to the diagonal sheathing, but it is easier and more flexible to manufacture. The diagonal sheathing type is stronger and stiffer because it has triangulation properties, such as truss properties, but is more complicated to manufacture (less flexible). The type A design is suitable for low-intensity zones (2), and types B, D, E1 and E2 are suitable for moderate-intensity zones (3, 4), and type C is suitable for severe-intensity zones (5).
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Influence of inter-panel connections on vibration response of CLT floors due to pedestrian-induced loading

https://research.thinkwood.com/en/permalink/catalogue3340
Year of Publication
2023
Topic
Connections
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Milojevic, Marija
Racic, Vitomir
Marjanovic, Miroslav
Nefovska-Danilovic, Marija
Organization
University of Belgrade
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Acoustics and Vibration
Keywords
Walking Forces
Human-induced Vibrations
Single Surface Spline
Half-lapped Joint
Research Status
Complete
Series
Engineering Structures
Summary
Long-span cross-laminated timber (CLT) floors are typically an assembly of prefabricated CLT panels connected together on the site. The actual connections are commonly neglected in design calculations. Hence, a CLT floor is modelled either as a monolith slab or more frequently as a set of CLT panels with no connections at all. This paper presents a numerical study designed to examine the influence of two most common inter-panel connections, i.e. single surface spline and half-lapped joint, on vibration modes and vibration responses of a range of different CLT floors due to pedestrian-induced loading. Although the inter-panel connections are relatively complex in reality, they are modelled here as an equivalent 2D elastic strip between the CLT panels. This relatively simple yet robust model can be used with ease in design practice, regardless finite element (FE) software used to extract vibration modes of a CLT floor. The corresponding monolith floors and floors without inter-panel connections are studied for the comparison of the results. Vertical vibration responses are simulated for low-frequency and high-frequency floors using the corresponding walking force models given in a popular design guideline for footfall induced vibrations of civil engineering structures. Vibration responses were calculated for single pedestrian occupants and their walking paths parallel and perpendicular to the line of connection. The results showed that including the inter-panel connections in a FE model resulted in up to 2.5 higher RMS acceleration levels. Hence, the common practice of modelling CLT floors as monolith slabs or as a set of panels without connections should be left behind.
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Experimental and theoretical investigation on shear performances of glued-in perforated steel plate connections for prefabricated timber–concrete composite beams

https://research.thinkwood.com/en/permalink/catalogue3373
Year of Publication
2023
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Beams
Floors
Author
Yang, Huifeng
Lu, Yan
Ling, Xiu
Tao, Haotian
Shi, Benkai
Organization
Nanjing Tech University
Southeast University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Timber-Concrete Composite
Application
Beams
Floors
Topic
Mechanical Properties
Keywords
Glued-in Perforated Steel Plate
Prefabricated Concrete Slab
Slip Modulus
Experimental Study
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
Glued-in perforated steel plate (GIPSP) connections demonstrate significant shear strength and high slip modulus. Consequently, they indicate substantial potential for application in timber–concrete composite (TCC) structures according to the emerging tendencies in high-storey and large-span buildings. However, the application pattern in prefabricated TCC structures and the theoretical analysis of the shear performances of GIPSP connections are highly deficient. This hinders the application of this type of shear connection. In this study, the shear performances of GIPSP connections were evaluated using push-out tests. Ten groups of push-out specimens with different steel plate numbers, steel plate lengths, and concrete slab types were tested. The concrete slab types investigated in the experiments included a prefabricated concrete slab and cast-in-situ concrete slab. The experimental results were discussed in terms of the failure mode, load-carrying capacity, and slip modulus. The theoretical models for the load-carrying capacity related to the associate failure mode were discussed based on an analysis of the failure mechanisms. In addition, design proposals with regard to the load-carrying capacity and slip modulus of the GIPSP connection were presented. The research results can provide design guidance for TCC beams using GIPSP connections and prefabricated concrete slabs.
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Design of a novel seismic retrofitting system for RC structures based on asymmetric friction connections and CLT panels

https://research.thinkwood.com/en/permalink/catalogue2912
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Aloisoio, Angelo
Boggian, Francesco
Tomasi, Roberto
Organization
Università degli Studi dell’Aquila
Università degli Studi di Trento
Norwegian University of Life Science
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Seismic
Keywords
Friction-based Device
Seismic Protection
Structural Design
Reinforced-concrete Structures
Research Status
Complete
Series
Engineering Structures
Summary
Friction-based dampers are a valid solution for non-invasive seismic retrofitting interventions of existing structures, particularly reinforced-concrete (RC) structures. The design of friction-based dampers is challenging: underestimating the slip force prevents the full use of the potential of the device, which attains the maximum admissible displacement earlier than expected. By contrast, overestimating the slip force may cause delayed triggering of the device when the structure has suffered extensive damage. Therefore, designing the appropriate slip force is an optimization problem. The optimal slip force guarantees the highest inter-story drift reduction. The authors formulated the optimization problem for designing a specific class of friction-based dampers, the asymmetric friction connection (AFC), devised as part of the ongoing multidisciplinary Horizon 2020 research project e-SAFE (Energy and Seismic AFfordable rEnovation solutions). The seismic retrofitting technology involves the external application of modular prefabricated cross-laminated timber (CLT) panels on existing external walls. Friction dampers connect the CLT panels to the beams of two consecutive floors. The friction depends on the mutual sliding of two metal plates, pressed against each other by preloaded bolts. This study determines the optimal slip force, which guarantees the best seismic performance of an RC structural archetype. The authors investigate the nonlinear dynamic response of a coupled mechanical system (RC frame-friction damper) under a set of strong-motion earthquakes, using non-differential hysteresis models calibrated on the experimental cyclic responses. The solution of the optimization leads to the proposal of a preliminary simplified design procedure, useful for practitioners.
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An experimental and modeling study on apparent bending moduli of cross-laminated bamboo and timber (CLBT) in orthogonal strength directions

https://research.thinkwood.com/en/permalink/catalogue2914
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Hao
Wang, Brad
Wang, Libin
Wei, Yang
Organization
Nanjing Forestry University
Southwest Forestry University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending Performance
Modeling Analysis
Cross-laminated Bamboo and Timber
Research Status
Complete
Series
Case Study in Construction Materials
Summary
In this paper, the bending properties of a 3-ply cross-laminated bamboo and timber (CLBT), prefabricated with the bamboo mat-curtain panel and hem-fir lumber, were examined in the major and minor strength directions, and a 3-ply hem-fir cross-laminated timber (CLT) was taken as a control group. The analytical model for the sum of the orthogonal apparent bending moduli with the two types of layer classifications were proposed, and the two kinds of contribution models were developed to analyze the apparent bending modulus variation behavior of the CLBT and CLT panels in the major and minor strength directions. The experimental results showed that since the CLBT group had more internal orthogonal structures, its difference in the bending properties between the major and minor strength directions was lower than that of the CLT group. Furthermore, the proposed contribution models quantitatively analyzed the relationship between the apparent bending moduli of the CLBT and CLT panels and the corresponding composition layer characteristics. The contribution model to characterize the apparent bending modulus in major and minor strength directions demonstrated good agreement with the test results. Based on this model interpreted by three-dimensional figures, the contribution variation characteristics in the major and minor strength directions were revealed.
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A numerical and experimental investigation of non-linear deformation behaviours in light-frame timber walls

https://research.thinkwood.com/en/permalink/catalogue3022
Year of Publication
2022
Topic
Mechanical Properties
Application
Walls
Shear Walls
Author
Kuai, Le
Ormarsson, Sigurdur
Vessby, Johan
Maharjan, Rajan
Organization
Linnaeus University
Karlstad University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Application
Walls
Shear Walls
Topic
Mechanical Properties
Keywords
Timber Structures
Internal Force Distribution
Light-frame Shear Walls
Parametric Study
Openings
Research Status
Complete
Series
Engineering Structures
Summary
In recent decades, there is a trend in Scandinavian countries to build multi-storey residential houses using prefabricated timber modules. It is a highly efficient construction process with less environmental impact and less material waste. A significant building element in the timber modules is the light-frame timber wall, which has to be carefully analysed and optimized in this process. This paper presents a new parametric Finite Element (FE) model that can simulate both in-plane and out-of-plane deformations in the light-frame walls. A new and flexible (Eurocode based) approach to define the properties of the mechanical connections is introduced. A numerical model is presented through simulations of several walls that were verified with full-scale experiments. The results indicate that the numerical model could achieve fairly reasonable accuracy with the new approach. Furthermore, several parametric studies are presented and discussed from global and local points of view, to investigate the effects of certain parameters that are not considered in the design method according to Eurocode 5.
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Technical Guide for the Design and Construction of Tall Wood Buildings in Canada

https://research.thinkwood.com/en/permalink/catalogue3034
Edition
Second Edition
Year of Publication
2022
Topic
Design and Systems
Application
Wood Building Systems
Organization
FPInnovations
Editor
Karacabeyli, Erol
Lum, Conroy
Edition
Second Edition
Year of Publication
2022
Format
Book/Guide
Application
Wood Building Systems
Topic
Design and Systems
Keywords
Engineered Wood Products
Mass Timber Construction
Tall Wood Buildings
Hybrid Tall Wood Buildings
Cost
Sustainability
Serviceability
Seismic
Fire Safety
Building Enclosure
Prefabrication
Monitoring
Maintenance
Research Status
Complete
Summary
Since the publication of the first edition of this guide, substantial regulatory changes have been implemented in the 2020 edition of the National Building Code of Canada: the addition of encapsulated mass timber construction up to 12 storeys, and the early adoption of the related provisions by several provinces are the most notable ones. The 2022 edition of this guide brings together, under one cover, the experience gained from recently built tall wood projects, highlights from the most recent building codes and standards, and research findings to help achieve the best environmental, structural, fire, and durability performance of mass timber products and systems, including their health benefits. The approaches to maximizing the benefits of prefabrication and building information modelling, which collectively result in fast, clean, and quiet project delivery, are discussed. Methods for addressing limitations controlled by fire requirements (through an Alternative Solution) or seismic requirements (through a hybrid solution using an Acceptable Solution in steel or concrete) are included. How best to build with mass timber to meet the higher performance requirements of the Energy Step Codes is also discussed. What makes building in wood a positive contribution toward tackling climate change is discussed so that design teams, in collaboration with building owners, can take the steps necessary to meet either regulatory or market requirements.
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Experimental and numerical study on the bending response of a prefabricated composite CLT-steel floor module

https://research.thinkwood.com/en/permalink/catalogue3047
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Owolabi, David
Loss, Cristiano
Organization
University of British Columbia
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Composite Floors
Hybrid Construction
Mass Timber
Cross-laminated Timber
Prefabricated Construction
Low-Carbon Structures
Bending Stiffness
Research Status
Complete
Series
Engineering Structures
Summary
Cross-laminated timber (CLT) is one of the most widely utilized mass timber products for floor construction given its sustainability, widespread availability, ease of fabrication and installation. Composite CLT-based assemblies are emerging alternatives to provide flooring systems with efficient design and optimal structural performance. In this paper, a novel prefabricated CLT-steel composite floor module is investigated. Its structural response to out-of-plane static loads is assessed via 6-point bending tests and 3D finite-element computational analysis. For simply supported conditions, the results of the investigation demonstrate that the floor attains a high level of composite efficiency (98%), and its bending stiffness is about 2.5 times those of its components combined. Within the design load range, the strain diagrams are linear and not affected by the discontinuous arrangement and variable spacing of the shear connectors. The composite floor module can reach large deflection without premature failure in the elements or shear connectors, with plasticity developed in the cold-formed steel beams and a maximum attained load 3.8 times its ultimate limit state design load. The gravity design of the composite module is shown to be governed by its serviceability deflection requirements. However, knowledge gaps still exist on the vibration, fire, and long-term behaviour of this composite CLT-steel floor system.
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Timber-concrete composite structural flooring system

https://research.thinkwood.com/en/permalink/catalogue3065
Year of Publication
2022
Topic
Mechanical Properties
Design and Systems
Material
Timber-Concrete Composite
Application
Floors
Author
Estévez-Cimadevila, J.
Martín-Gutiérrez, E.
Suárez-Riestra, F.
Otero-Chans, D.
Vázquez-Rodríguez, J. A.
Organization
Universidade da Coruña
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Design and Systems
Keywords
Timber Flooring System
Mixed Beams
Shear Connector
Research Status
Complete
Series
Journal of Building Engineering
Summary
An integrated solution is presented for the execution of building structures using timber-concrete composite (TCC) sections that make efficient use of the mechanical properties of both materials. The system integrates flooring and shaped prefabricated beams composed of a lower flange of glued laminated timber (GLT) glued to one or more plywood or laminated veneer lumber (LVL) ribs and linked to an upper concrete slab poured in situ. The parts may be prefabricated in T shape (only one rib), in p shape (two ribs), or with multiple ribs to create wider pieces, thereby reducing installation operations. The basis of the system is the timber-concrete shear connection in the form of holes through the ribs, which are filled by the in situ-poured concrete. The connection is complemented with the arrangement of reinforcement bars through the holes. Three test campaigns were undertaken. Shear tests of the timber-concrete connection in 12 test pieces. Shear test along the wood-wood glue line (72 planes tested) and wood -plywood (24 planes tested). Delamination test of the glued planes (24 wood-wood planes and 8 wood-plywood planes). The results indicate a high strength joint, with ductile failure and high composite effect. Likewise, the shear test results along the glue line and the delamination tests show section integrity under demanding hygrothermal conditions. Preliminary sizing curves were developed considering the Gamma Method to evaluate the performance of the system. The results show the possibilities of the system, as pouring the upper slab concrete in situ makes it possible to create continuous semi-rigid joints between the elements. This gives rise to slender flooring structures, light and with high stiffness plane against horizontal forces.
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Innovations in mass timber lateral systems

https://research.thinkwood.com/en/permalink/catalogue3099
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Bailey, Dawson
Organization
Kansas State University
Year of Publication
2022
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Rocking Timber Walls
Lateral Systems
Post Tensioning
Research Status
Complete
Summary
As mass timber becomes increasingly popular in the United States and around the world, there comes more demand for mass timber in larger buildings. With this demand comes a necessity for these buildings to be able to withstand seismic forces; and in some locations, these forces can get quite high. Typical mass timber lateral systems (such as CLT shear walls) have worked fine for lower seismic forces and shorter buildings, but with this new demand comes a need for newer systems. Rocking timber walls is one of these systems. The goal of a rocking timber wall is to allow the lateral wall system to move in the case of high seismic force, thus reducing the loading the wall experiences. This is done with vertical post tensioning (PT) within cross-laminated timber panels (CLT). In addition, easily replaceable energy dissipation devices, such as U-shaped flexural plates (UFPs), allow for concentration of inelastic deformation during rocking of the walls, which keeps the CLT and PT components free from harm. Another system used to handle seismic load in tall mass timber structures are inter-story isolation systems. These systems can isolate the force at separate levels, effectively decreasing the load the foundation takes from the building's movement. Even newer than these systems is the Floor Isolated Re-centering Modular Construction System (FIRMOC), which utilizes rocking timber walls, inter-story isolation, and the addition of prefabricated modular mass timber to create a system capable of effectively and efficiently dealing with large seismic forces. This report seeks to present these innovative, capable, and effective lateral systems for seismic forces in large scale mass timber structures in a manner that provides understanding of how they work and what makes them effective.
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Hybrid simulation of a post-tensioned timber frame and validation of numerical models for seismic design

https://research.thinkwood.com/en/permalink/catalogue3107
Year of Publication
2022
Topic
Seismic
Application
Frames
Author
Ogrizovic, J.
Abbiati, G.
Stojadinovic, B.
Frangi, A.
Organization
MWV Bauingenieure
University of Aarhus
ETH Zurich
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Application
Frames
Topic
Seismic
Keywords
Post-tensioned Timber Frame
Seismic Analysis
Hybrid Simulation
Finite Element Modeling
Research Status
Complete
Series
Engineering Structures
Summary
The post-tensioned frame is one of the recently emerged structural systems for multi-story timber buildings. It is characterized by a high level of prefabrication and quick erection on the construction site. The post-tensioned frame developed at ETH Zurich is based on post-tensioned beam–column connections with hardwood reinforcement of the column in the connection region and column base connections with glued-in steel rods. Such a construction system is suitable for low- and mid-rise buildings that are located in regions characterized by low to moderate seismicity. This paper presents a series of hybrid simulations of the response of a two-story two-bay post-tensioned timber frame subjected to ground motion excitation. Nonlinear numerical models of both beam–column and column base connections to be used for design purposes are validated based on the experiments.
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Behavior of timber-concrete composite with defects in adhesive connection

https://research.thinkwood.com/en/permalink/catalogue3108
Year of Publication
2022
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Buka-Vaivade, Karina
Serdjuks, Dmitrijs
Organization
Riga Technical University
Publisher
Elsevier
Year of Publication
2022
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Adhesive Connection
Rigid Connection
Conference
ICSI 2021 The 4th International Conference on Structural Integrity
Research Status
Complete
Series
Procedia Structural Integrity
Summary
Rigid timber to concrete connection is the most effective solution for timber-concrete composite members subjected to the flexure which provides full composite action and better structural behaviour. One of the most used technologies to produce glued connection of the timber-concrete composite is “dry” method, which includes gluing together of timber and precast concrete slab. This technique has high risk of forming a poor-quality rigid connection in timber-concrete composite, and there are difficulties in controlling the quality of the glued connection. The effect of the non-glued areas in connection between composite layers on the shear stresses and energy absorption were investigated by finite element method and laboratorian experiment. Three timber-concrete composite panels in combination with carbon fibre reinforced plastic composite tapes in the tension zone with the span 1.8 m were statically loaded till the failure by the scheme of three-point bending. Mid-span displacements were measured in the bending test. One specimen was produced by dry method, by gluing together cross-laminated timber panel and prefabricated concrete panel. Timber-concrete qualitative connection of the other two specimens was provided by the granite chips, which were glued on the surface of the cross-laminated timber by epoxy, and then wet concrete was placed. Dimensions of the crushed granite pieces changes within the limits from 16 to 25 mm. The investigated panel with different amount and sizes of non-glued areas in the timber to concrete connection was numerically modelled. Obtained results shown, that the increase of shear stresses is influenced not so much by a total amount of non-glued areas, but by the size of the individual defective areas. Moreover, large non-glued areas significantly reduce the energy absorption of elements subjected to the flexure, which was observed experimentally for defective panel produced by the classical dry method with almost 4 times larger mid-span displacements than for panel with full composite action provided by the proposed production technology of the timber to concrete rigid connection. So, the proposed technology based on the use of granite chips, provides a high-quality connection between timber and concrete layers, with insignificant ration between possible defect and total connection surface area, which is equal to the area of one granite chips edge.
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A study on beam-to-column moment-resisting timber connections under service load, comparing full-scale connection testing and mock-up frame assembly

https://research.thinkwood.com/en/permalink/catalogue3116
Year of Publication
2022
Topic
Connections
Application
Frames
Author
Vilguts, Aivars
Nesheim, Sveinung Ørjan
Stamatopoulos, Haris
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Application
Frames
Topic
Connections
Keywords
Moment-resisting Connection
Semi-rigid Connection
Screwed-in Threaded Rods
Experimental Modal Analysis
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
A new timber frame structural system consisting of continuous columns, prefabricated hollow box timber decks and beam-to-column moment-resisting connections is investigated. The hollow box timber decks allow long spans with competitive floor height and efficient material consumption. To achieve long spans, semi-rigid connections at the corners of deck elements are used to join the columns to the deck elements. In the present paper, experimental investigations of a semi-rigid moment-resisting connection and a mock-up frame assembly are presented. The semi-rigid connection consists of inclined screwed-in threaded rods and steel coupling parts, connected with friction bolts. Full-scale moment-resisting timber connections were tested under monotonic and cyclic loading to quantify rotational stiffness, energy dissipation and moment resistance. The mock-up frame assembly was tested under cyclic lateral loading and with experimental modal analysis. The lateral stiffness, energy dissipation, rotational stiffness of the connections and the eigen frequencies of the mock-up frame assembly were quantified based on the experimental tests in combination with a Finite Element model, i.e., the model was validated with experimental results from the rotational stiffness tests of the beam-to-column connections. Finally, the structural damping measured with experimental modal analysis was evaluated and compared with FE model using the material damping of timber parts and equivalent viscous damping of the moment-resisting connections.
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Structural Performance of Mass Timber Panel-Concrete Composite Floors with Notched Connections

https://research.thinkwood.com/en/permalink/catalogue3122
Year of Publication
2022
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Zhang, Lei
Organization
University of Alberta
Year of Publication
2022
Format
Thesis
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Notched Connection
Discrete Bond Composite Beam Model
Mass Timber Panel
Connection Stiffness
Effective Bending Stiffness
Load-Carrying Capacity
Research Status
Complete
Summary
This thesis focuses on the structural performance of mass timber panel-concrete composite floors with notches. Mass timber panels (MTPs) such as cross-laminated timber, glue-laminated timber, and nail-laminated timber, are emerging construction materials in the building industry due to their high strength, great dimensional stability, and prefabrication. The combination of MTPs and concrete in the floor system offers many structural, economic, and ecological benefits. The structural performance of MTP-concrete composite floors is governed by the shear connection system between timber and concrete. The notched connections made by cutting grooves on timber and filling them with concrete are considered as a structurally efficient and cost-saving connecting solution for resisting shear forces and restricting relative slips between timber and concrete. However, the notched connection design in the composite floors is not standardized and the existing design guidelines are inadequate for MTP-concrete composite floors. To study the structural performance of notched connections and notch-connected composite floors, this thesis presented experimental, numerical, and analytical investigations. Push-out tests were conducted on the notched connections first, and then bending tests and vibration tests were conducted on full-scale composite floors. Finite element models were built for the notched connections to derive the connection shear stiffness. Finally, analytical solutions were developed to predict the internal actions of the composite floors under external loads. This study shows that the structural performance of notched connections is affected by the geometry of the connections and material properties of timber and concrete. The notch-connected MTP-concrete composite floors showed high bending stiffness but were not fully composite. The floors with shallow notches tended to fail in a ductile manner but had lower bending stiffness than floors with deep notches. The composite floors with deep notches, however, often fail abruptly in the concrete notches. By reinforcing the notched connections with steel fasteners, the composite floor can achieve high bending stiffness, high load-carrying capacity, and controlled failure pattern. The proper number and locations of notched connections in the composite floors can be determined from the proposed composite beam model. This thesis presented promising results in terms of the static and dynamic structural performance of notch-connected MTP-concrete composite floors. The test investigations added additional data to the current research body and prompted further evolvement of timber-concrete composite floors. The proposed empirical equations for estimating the connection stiffness and strength and composite beam model for predicting the serviceability and ultimate structural performance of composite floors provide useful tools to analyze the notch-connected MTP-concrete composite floors. The design recommendations for MTP-concrete composite floors with notches are provided in the thesis.
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Free
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Structural Analysis and Design of Sustainable Cross-Laminated Timber Foundation Walls

https://research.thinkwood.com/en/permalink/catalogue3151
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Daneshvar, Hossein
Fakhrzarei, Mahboobeh
Imamura, Fernanda
Chen, Yuxiang
Deng, Lijun
Chui, Ying Hei
Organization
University of Alberta
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Keywords
Foundation Walls
Basement
Crawl Space
Sustainability
Research Status
Complete
Series
Buildings
Summary
There is widespread enthusiasm toward utilizing mass timber panels (MTP), mainly cross-laminated timber (CLT), in construction, including for the basements of low-rise buildings. CLT is deemed a sustainable alternative to the widely used concrete foundation walls due to significant advantages such as less vulnerability to cracking due to uneven load distribution and presence of concentrated loads, higher thermal resistance, less construction time due to whole-wall prefabrication and installation, and less detrimental environmental effects. This study is part of an extensive research program aimed at developing the structural analysis and design concepts and methodology for constructing house foundation walls using MTPs, focusing on the usage of CLT. After comparison of CLT basements with their equivalent concrete ones from the sustainability point of view, and a brief discussion on geotechnical and hygrothermal considerations, the main theme of the article includes the structural analysis and design methodology, requirements, and the procedure to achieve a reliable and efficient design of a CLT basement. A simplified analysis procedure to design the laminate thicknesses and the number of layers in CLT foundation walls for different scenarios considering various variables such as soil type and backfill height is discussed, and results in the form of pre-engineered design tables are provided. The findings of this study demonstrate that, depending on the soil type and backfill height, 3–7-ply CLT panels would be needed for net wall heights of up to 3 m. Additionally, advanced finite element analyses are performed on sample architypes to validate the simplified analysis procedure used for design. It is shown that the proposed analysis procedure and the pre-engineered tables produce conservative and efficient results.
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Free
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An Empirical Analysis of Barriers to Building Information Modelling (BIM) Implementation in Wood Construction Projects: Evidence from the Swedish Context

https://research.thinkwood.com/en/permalink/catalogue3155
Year of Publication
2022
Topic
General Information
Author
Gharaibeh, Lina
Matarneh, Sandra T.
Eriksson, Kristina
Lantz, Björn
Organization
University West
Al-Ahliyya Amman University
Editor
Ullah, Fahim
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Topic
General Information
Keywords
Building Information Modelling
Wood Construction
Grounded Theory
Research Status
Complete
Series
Buildings
Summary
Building information modelling is gradually being recognised by the architecture, engineering, construction, and operation industry as a valuable opportunity to increase the efficiency of the built environment. Focusing on the wood construction industry, BIM is becoming a necessity; this is due to its high level of prefabrication and complex digital procedures using wood sawing machines and sophisticated cuttings. However, the full implementation of BIM is still far from reality. The main objective of this paper is to explore the barriers affecting BIM implementation in the Swedish construction industry. An extensive literature review was conducted to extract barriers hindering the implementation of BIM in the construction industry. Secondly, barriers to the implementation of BIM in the wood construction industry in Sweden were extracted using the grounded theory methodology to analyse expert input on the phenomenon of low BIM implementation in the wood construction industry in Sweden. Thirty-four barriers were identified. The analysis of this study also led to the development of a conceptual model that recommended solutions to overcome the barriers identified to help maximise BIM implementation within the wood construction industry. Identifying the main barriers affecting BIM implementation is essential to guide organisational decisions and drive policy, particularly for governments that are considering articulating regulations to expand BIM implementation.
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Free
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Energy performance of a prefabricated timber-based retrofit solution applied to a pilot building in Southern Europe

https://research.thinkwood.com/en/permalink/catalogue3158
Year of Publication
2022
Topic
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Evola, Gianpiero
Costanzo, Vincenzo
Urso, Alessandra
Tardo, Carola
Margani, Giuseppe
Organization
University of Catania
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Energy Performance
Keywords
Timber-based Retrofit
Thermal Insulation
Thermal Bridges
Dynamic Simulations
Space Heating
Space Cooling
Research Status
Complete
Series
Building and Environment
Summary
This paper advances the current knowledge on the use of prefabricated timber-based panels in building renovation by analyzing in detail the thermal performance achieved by two different renovation solutions developed in the framework of the ongoing e-SAFE H2020 project. In particular, these solutions apply to the external walls of a pilot building located in Catania (Italy) as a double-skin façade that increases also the seismic performance of the building. The dynamic energy simulations reveal that the proposed solutions allow reducing the energy need for space heating and space cooling by 66% and 25%, respectively. One further finding is that, although the proposed timber-based renovation solutions are not affected by mould growth and surface condensation risk, the impact of thermal bridges cannot be neglected after renovation. Indeed, despite the strong reduction in the magnitude of heat losses due to thermal bridges (from 667 W·K-1 down to 213.1 W·K-1), they still account for about 21% of total heat losses after the renovation. This suggests that more complex and expensive technological solutions should be introduced to further reduce heat losses in some thermal bridges, but a cost-benefit analysis should justify their adoption. Finally, overlooking these thermal bridges in dynamic energy simulations can lead to an average underestimation of the heating and cooling energy demand after the renovation, by about 16% and 5% respectively. In this regard, the paper proposes a simplified yet reliable approach to include heat transfer through thermal bridges in the post-processing stage of dynamic energy simulations under thermostatic control.
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Obstacles Preventing the Off-Site Prefabrication of Timber and MEP Services: Qualitative Analyses from Builders and Suppliers in Australia

https://research.thinkwood.com/en/permalink/catalogue3160
Year of Publication
2022
Topic
General Information
Author
Lopez, Robert
Chong, Heap-Yih
Pereira, Conrad
Organization
Curtin University
Nanjing Audit University
Editor
Santos, Paulo
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Topic
General Information
Keywords
Construction
Collaboration
Coordination
MEP
Off-site
On-Site
In Situ
Prefabrication
Builder
Supplier
Australia
Research Status
Complete
Series
Buildings
Summary
Limited empirical and qualitative studies focus on the detailed processes and obstacles for coordinating off-site prefabrication between builders and suppliers. This research aims to identify and address the obstacles that currently prevent the further expansion of off-site prefabrication, with a research scope on timber and mechanical/electrical/plumbing (MEP) services in construction projects. The focal point of this research is to highlight their obstacles. A total of forty interviews were conducted and analyzed from four builders’ organizations and four suppliers’ organizations to ascertain their obstacles in coordinating the practice of off-site prefabrication. The results found the builder’s obstacles were sustainability, quality assurance (QA), mass production, CAD/BIM, technological support, commercial arrangements, system building, buffering in supply, schedule monitoring, productivity, flexibility, engagement, risks, and multiple supply arrangements. The supplier’s obstacles were design, financing and subcontracting, coordination, recognized practices, risks, multiple supply arrangements, and constraints. Moreover, the builders and suppliers had identified some ways to harmonize off-site prefabrication of timber. Some examples of timber prefabrication technology include joinery, doors and/or windows, structural floor/wall/roof frames, partitions, trusses, stairs, balustrades, and others. MEP services with in situ construction comprise the use of power sources and working coordination. The most important outcome of this investigation is that these obstacles can be addressed through collaboration and coordination. This is because there is a traditionally a lack of collaboration amongst builders and their suppliers. Furthermore, there is a lack of coordination between them in general. The research contributes to the improved timber and MEP services collaboration and coordination in off-site prefabrication, which can be referred to by other approaches of modular construction.
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Free
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Design Development for a Forestry Experience Center Building Demonstrating New, Scalable, Prefabricated Mass-Timber Components

https://research.thinkwood.com/en/permalink/catalogue3180
Year of Publication
2022
Organization
World Forestry Center
Year of Publication
2022
Keywords
Prefabricated
Demonstration
Research Status
In Progress
Notes
Forest Service/USDA Wood Innovations Grants Recipient Point of Contact: Sarah Horton Location: Portland, Oregon
Summary
World Forestry Center (WFC) requests USFS funds to support the Design Development, costing, and Construction Document phases for a new Forestry Experience Center. The goal of this project is to create a demonstration site for scalable, factory-made mass timber buildings that will act as a model for building technologies that advance solutions to climate change. WFC is a 501(c)3 non-profit organization headquartered in Portland, Oregon, and located in Portland’s Washington Park, which attracts over 3 million visitors each year. Our mission is to create and inspire champions of sustainable forestry. Our programs are designed to shape a society that values and takes action in support of the economic, ecological, and social benefits of forests. The new 27,300 square-foot Forestry Experience Center will include an exhibit hall, event space, a café, office space, and a “gateway” structure that will connect Washington Park visitors to WFC, Washington Park, Forest Park, and beyond. WFC has been working with Sidewalk Labs as a design consultant to incorporate Sidewalk Labs’ prefabricated modular mass timber building elements into early conceptual design. The new building will demonstrate how these products can be adopted at scale across the construction sector for mid-rise buildings, with competitive costs on par with expectations for timber or other conventional materials, and with greater environmental and social benefits. Interactive, emotionally-resonant exhibits on forestry’s most urgent challenges will be the focal point of programming within the new Forestry Experience Center. The building itself will serve as a tool to drive a public narrative about the benefits of prefabricated mass timber construction. The design will be enhanced by interpretive elements that will connect visitors to the products and techniques employed throughout the structure and the role these innovations play in improving the health of our forests and quality of life in our communities.
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